According to one embodiment illustrated in FIG. 1, an aircraft 10 comprises, at the leading edge 12 and at the trailing edge 14 of each wing 16, high-lift devices which allow the profile of the wing 16 to be modified in order to increase its lift in order to allow the aircraft 10 to fly at low speed in complete safety, for example during the phases of takeoff or landing.
As illustrated in FIG. 2, each high-lift device comprises, at each leading or trailing edge 12, 14, flaps 18 that are mobile between a retracted position in the wing 16 and a deployed position out of the wing 16. For each trailing or leading edge 12, 14, the movement of deploying or retracting the set of flaps 18 is simultaneous and brought about by a plurality of actuators 20 which are connected to one and the same kinematic chain 22 which comprises a plurality of shafts 24 rotating on themselves and arranged end to end.
Each kinematic chain 22 comprises a first shaft coupled to a drive 26 configured to drive the rotation of all the shafts 24 of the kinematic chain 22 and thus, depending on the direction of rotation, bring about the movement that deploys or retracts the flaps 18. The kinematic chain 22 comprises a plurality of coupling systems 28, all identical, each of them connecting two successive shafts 24 or connecting a shaft 24 and an actuator 20.
As illustrated in FIG. 3, when a first flap 18.1 is to be removed during a maintenance operation, a first shaft 24.1 is removed. After that, an adapter is secured to one of the coupling systems 28.1 freed by the first shaft 24.1. This adapter is coupled to an external drive to cause the shafts 24 situated downstream of the removed first shaft 24.1 to pivot so as to cause the first flap 18.1 to deploy to make it easier to remove.
As illustrated in FIG. 4, when a second flap 18.2 is to be removed during a maintenance operation, a second shaft 24.2 and a third shaft 24.3 are removed. After that, an adapter is secured to one of the coupling systems 28.2 revealed by the second shaft 24.2. This adapter is coupled to an external drive to cause the shafts 24 positioned between the removed second and third shafts 24.2 and 24.3 to pivot in order to cause the second flap 18.2 to deploy to make it easier to remove.
During the removal operation, it is absolutely imperative that the adapter be coupled to the appropriate coupling system. If it is not, there is a great risk that at least one of the flaps will become damaged.
Now, there is no way of indicating to an operator that the adapter is not coupled to the appropriate coupling system before the external drive is set to rotate.